Light-trail network is a novel optical network which takes advantage of mature optical devices to assign the bandwidth and switch the packets flexibly. Crosstalk is an important factor to restrict the performance at the physical layer as well as the extensibility of the light-trail network. Firstly, the causes of both interband crosstalk and intraband crosstalk in the typical light-trail nodes are discussed. In addition, the influence of the two kind’s crosstalk on the transmission performance at the physical layer is theoretically analyzed. Secondly, three methods to evaluate the crosstalk are introduced. On the basis of DWDM technique, a simulation platform with 3 nodes and 5 wavelengths is built, in which the optical devices are assigned optical depth as 20 dB and 30 dB. And the basic transmission rate of the wavelength is 2.5 Gbps. At last, the propagation process of the crosstalk is traced in the whole light-trail network. And the BER, the power penalty and the relative crosstalk are calculated accordingly. Both analytical and simulation results show that optical filter, demultiplexer and multiplexer are the key optical devices which cause crosstalks. Hence, the transmission performance of light-trail network can be enhanced obviously by improving the depth of the above optical devices. Moreover, both BER and power penalty are observed to be affected deeply by the crosstalk when the basic transmission rate of single wavelength is up to 2.5 Gbps. Therefore, the number of optical node available is limited at the scenario of DWDM.